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Fan Y, Wang L, Putnis CV, Zhang W. Direct Nanoscale Imaging Reveals the Mechanism by Which Organic Acids Dissolve Vivianite through Proton and Ligand Effects. Inorg Chem 2024; 63:6909-6921. [PMID: 38564449 DOI: 10.1021/acs.inorgchem.4c00353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The coprecipitation of iron (Fe) and phosphorus (P) in natural environments limits their bioavailability. Plant root-secreted organic acids can dissolve Fe-P precipitates, but the molecular mechanism underlying mobilizing biogenic elements from highly insoluble inorganic minerals remains poorly understood. Here, we investigated vivianite (Fe3(PO4)2·8H2O) dissolution by organic acids (oxalic acid (OA), citric acid (CA), and 2'-dehydroxymugineic acid (DMA)) at three different pH values (4.0, 6.0, and 8.0). With increasing pH, the vivianite dissolution efficiency by OA and CA was decreased while that by DMA was increased, indicating various dissolution mechanisms of different organic acids. Under acidic conditions, weak ligand OA (HC2O4- > C2O42- at pH 4.0 and C2O42- at pH 6.0) dissolved vivianite through the H+ effect to form irregular pits, but under alkaline condition (pH 8.0), the completely deprotonated OA was insufficient to dissolve vivianite. At pH 4.0, CA (H2Cit- > HCit2- > H3Cit) dissolved vivianite to form irregular pits through a proton-promoted mechanism, while at pH 6.0 (HCit2- > Cit3-) and pH 8.0 (Cit3-), CA dissolved vivianite to form near-rhombohedral pits through a ligand-promoted mechanism. At three pH values ((H0)DMA3- > (H1)DMA2- at pH 4.0, (H0)DMA3- at pH 6.0, and (H0)DMA3- and one deprotonated imino at pH 8.0), strong ligand DMA dissolved vivianite to form near-rhombohedral pits via ligand-promoted mechanisms. Raman spectroscopy showed that the deprotonated carboxyl groups (COO-) and imino groups were bound to Fe on the vivianite (010) face. The surface free energy of vivianite coated with OA decreased from 29.32 mJ m-2 to 24.23 mJ m-2 and then to 13.47 mJ m-2 with increasing pH, and that coated with CA resulted in a similar pH-dependent vivianite surface free-energy decrease while that coated with DMA increased the vivianite surface free energy from 31.92 mJ m-2 to 39.26 mJ m-2 and then to 49.93 mJ m-2. Density functional theory (DFT)-based calculations confirmed these findings. Our findings provide insight into the mechanism by which organic acids dissolved vivianite through proton and ligand effects.
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Affiliation(s)
- Yuke Fan
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- School of Molecular and Life Sciences, Curtin University, Perth 6845, Australia
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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2
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Ge X, Fan Y, Zhai H, Chi J, Putnis CV, Wang L, Zhang W. Direct observations of nanoscale brushite dissolution by the concentration-dependent adsorption of phosphate or phytate. Water Res 2024; 248:120851. [PMID: 37976955 DOI: 10.1016/j.watres.2023.120851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/05/2023] [Accepted: 11/08/2023] [Indexed: 11/19/2023]
Abstract
With the development of agricultural intensification, phosphorus (P) accumulation in croplands and sediments has resulted in the increasingly widespread interaction between inorganic and organic P species, which has been, previously, underestimated or even ignored. We quantified the nanoscale dissolution kinetics of sparingly soluble brushite (CaHPO4·2H2O, DCPD) over a broad range of phosphate and/or phytate concentrations by using in situ atomic force microscopy (AFM). Compared to water, we found that low concentrations of phosphate (1-1000 µM) or phytate (1-100 µM) inhibited brushite dissolution by slowing single step retraction. However, with increasing phosphate or phytate concentrations to 10 mM, there was a reverse effect of dissolution promotion at brushite-water interfaces. In situ observations of the coupled dissolution-reprecipitation showed that phosphate precipitated more readily than phytate on brushite surfaces, with the formation of amorphous calcium phosphate (ACP). For a fundamental understanding, zeta potential and in situ Raman spectroscopy (RS) revealed that the concentration-dependent dissolution is attributed to the reverse of outer-sphere to inner-sphere adsorption with increasing phosphate or phytate concentrations. In addition, the mineralization of phytate with outer-sphere adsorption by phytase was higher than that with inner-spere adsorption, and the presence of phytate delayed ACP phase transformation to hydroxylapatite (HAP). These in situ observations and analyses may fill the knowledge gaps of interaction between inorganic and organic P species in P-rich terrestrial and aquatic environments, thereby implicating their biogeochemical cycling and the associated availability.
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Affiliation(s)
- Xinfei Ge
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China; Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China
| | - Yuke Fan
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Hang Zhai
- Department of Civil and Environmental Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Jialin Chi
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, Münster 48149, Germany; School of Molecular and Life Sciences, Curtin University, Perth 6845, Australia
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
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3
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Bañuelos JL, Borguet E, Brown GE, Cygan RT, DeYoreo JJ, Dove PM, Gaigeot MP, Geiger FM, Gibbs JM, Grassian VH, Ilgen AG, Jun YS, Kabengi N, Katz L, Kubicki JD, Lützenkirchen J, Putnis CV, Remsing RC, Rosso KM, Rother G, Sulpizi M, Villalobos M, Zhang H. Oxide- and Silicate-Water Interfaces and Their Roles in Technology and the Environment. Chem Rev 2023; 123:6413-6544. [PMID: 37186959 DOI: 10.1021/acs.chemrev.2c00130] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Interfacial reactions drive all elemental cycling on Earth and play pivotal roles in human activities such as agriculture, water purification, energy production and storage, environmental contaminant remediation, and nuclear waste repository management. The onset of the 21st century marked the beginning of a more detailed understanding of mineral aqueous interfaces enabled by advances in techniques that use tunable high-flux focused ultrafast laser and X-ray sources to provide near-atomic measurement resolution, as well as by nanofabrication approaches that enable transmission electron microscopy in a liquid cell. This leap into atomic- and nanometer-scale measurements has uncovered scale-dependent phenomena whose reaction thermodynamics, kinetics, and pathways deviate from previous observations made on larger systems. A second key advance is new experimental evidence for what scientists hypothesized but could not test previously, namely, interfacial chemical reactions are frequently driven by "anomalies" or "non-idealities" such as defects, nanoconfinement, and other nontypical chemical structures. Third, progress in computational chemistry has yielded new insights that allow a move beyond simple schematics, leading to a molecular model of these complex interfaces. In combination with surface-sensitive measurements, we have gained knowledge of the interfacial structure and dynamics, including the underlying solid surface and the immediately adjacent water and aqueous ions, enabling a better definition of what constitutes the oxide- and silicate-water interfaces. This critical review discusses how science progresses from understanding ideal solid-water interfaces to more realistic systems, focusing on accomplishments in the last 20 years and identifying challenges and future opportunities for the community to address. We anticipate that the next 20 years will focus on understanding and predicting dynamic transient and reactive structures over greater spatial and temporal ranges as well as systems of greater structural and chemical complexity. Closer collaborations of theoretical and experimental experts across disciplines will continue to be critical to achieving this great aspiration.
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Affiliation(s)
- José Leobardo Bañuelos
- Department of Physics, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Eric Borguet
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Gordon E Brown
- Department of Earth and Planetary Sciences, The Stanford Doerr School of Sustainability, Stanford University, Stanford, California 94305, United States
| | - Randall T Cygan
- Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843, United States
| | - James J DeYoreo
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Patricia M Dove
- Department of Geosciences, Department of Chemistry, Department of Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Marie-Pierre Gaigeot
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, 91025 Evry-Courcouronnes, France
| | - Franz M Geiger
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Julianne M Gibbs
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2Canada
| | - Vicki H Grassian
- Department of Chemistry and Biochemistry, University of California, San Diego, California 92093, United States
| | - Anastasia G Ilgen
- Geochemistry Department, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Young-Shin Jun
- Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Nadine Kabengi
- Department of Geosciences, Georgia State University, Atlanta, Georgia 30303, United States
| | - Lynn Katz
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - James D Kubicki
- Department of Earth, Environmental & Resource Sciences, The University of Texas at El Paso, El Paso, Texas 79968, United States
| | - Johannes Lützenkirchen
- Karlsruher Institut für Technologie (KIT), Institut für Nukleare Entsorgung─INE, Eggenstein-Leopoldshafen 76344, Germany
| | - Christine V Putnis
- Institute for Mineralogy, University of Münster, Münster D-48149, Germany
| | - Richard C Remsing
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
| | - Gernot Rother
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Marialore Sulpizi
- Department of Physics, Ruhr Universität Bochum, NB6, 65, 44780, Bochum, Germany
| | - Mario Villalobos
- Departamento de Ciencias Ambientales y del Suelo, LANGEM, Instituto De Geología, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, Cleveland, Ohio 44106, United States
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Ge X, Zhang W, Putnis CV, Wang L. Direct observation of humic acid-promoted hydrolysis of phytate through stabilizing a conserved catalytic domain in phytase. Environ Sci Process Impacts 2022; 24:1082-1093. [PMID: 35730733 DOI: 10.1039/d2em00065b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
As a potential phosphorus (P) pool, the enzymatic hydrolysis of organic phosphorus (Po) is of fundamental importance due to the release of bioavailable inorganic phosphate (Pi) for agronomic P sustainability. However, little is known about the role of soil organic matter (SOM) in the hydrolysis process of phytate by phytase and the subsequent chemical behaviors involving the hydrolysis product (Pi) at different soil interfaces. Here, by using liquid-cell atomic force microscopy (AFM), we present a model system to in situ quantify the nucleation kinetics of phytase-released Pi when precipitating with representative soil multivalent cations (Ca2+/Fe3+) on typical soil mineral/organic interfaces in the presence/absence of humic acid (HA), which involves complex phytase-interface-HA interactions. We observed that a higher HA concentration resulted in a faster nucleation rate of amorphous calcium/iron phosphate (ACP/AIP) on bare and organically-coated (-OH/-COOH) mica surfaces compared with the HA-free control. Besides, the nucleation rate of ACP/AIP induced by organic interfaces was much more significant than that induced by clay mineral interfaces. By combining enzyme activity/stability experiments and AFM-based PeakForce quantitative nanomechanical mapping (PF-QNM) measurements, we directly quantified the contribution of noncovalent phytase-HA interaction to the increase in enzymatic activity from complex phytase-interface-HA interactions. Furthermore, the direct complexation of phytase-HA resulted in the stabilization of a conserved active catalytic domain (ACD) in phytase through the enhanced formation of both an ordered, stereochemically-favored catalytic domain and an unordered non-catalytic domain, which was revealed by Raman secondary structure determination. The results provide direct insights into how HA regulates the catalytic activity of phytase controlling Po fates and how soil interfaces determine the behaviors of released Pi to affect its availability, and thereby contribute to P sustainability in soils.
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Affiliation(s)
- Xinfei Ge
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, Münster 48149, Germany
- School of Molecular and Life Science, Curtin University, Perth 6845, Australia
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
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5
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Pu J, Putnis CV, Wang L. AFM imaging and single-molecule recognition of plant cell walls. Trends Plant Sci 2022; 27:412-413. [PMID: 34916130 DOI: 10.1016/j.tplants.2021.11.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/15/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Junbao Pu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany; School of Molecular and Life Sciences, Curtin University, Perth 6845, Australia
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
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6
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Ge X, Zhang W, Putnis CV, Wang L. Molecular mechanisms for the humic acid-enhanced formation of the ordered secondary structure of a conserved catalytic domain in phytase. Phys Chem Chem Phys 2022; 24:4493-4503. [PMID: 35113120 DOI: 10.1039/d2cp00054g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Changes in the secondary structure of phytase, particularly the conserved active catalytic domain (ACD, SRHGVRAPHD) are extremely important for the varied catalytic activity during hydrolyzing phytate in the presence of humic acid (HA). However, little is known about the molecular-scale mechanisms of how HA influences the secondary structure of ACD found in phytase. First, in situ surface-enhanced Raman spectroscopy (SERS) results show the secondary structure transformation of ACD from the unordered random coil to the ordered β-sheet structure after treatment with HA. Then, we use an atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS) technique that can in situ directly probe the single-molecule interaction of ACD with HA and underlying changes in ACD secondary structure in the approach-retraction cycles in real time. Based on the SMFS results, we further detect the HA-enhanced formation of H-bonding between amide groups in the ACD backbone after noncovalently interacting with HA in the absence of phytate. Following the addition of phytate, the calculated contour length (Lc) and the free energies (ΔGb) of functional groups within ACD(-1/2) binding to mica/HA collectively demonstrate the formation of the organized intermediate structural state of ACD following its covalent binding to phytate. These spectroscopic and single-molecule determinations provide the molecular-scale understanding regarding the detailed mechanisms of HA-enhancement of the ordered β-sheet secondary structure of ACD through chemical functionalities in ACD noncovalently interacting with HA. Therefore, we suggest that similar studies of the interactions of other soil enzymes and plant nutrients may reveal predominant roles of dissolved organic matter (DOM) in controlling elemental cycling and fate for sustainable agriculture development.
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Affiliation(s)
- Xinfei Ge
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany.,School of Molecular and Life Science, Curtin University, Perth 6845, Australia
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
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Pu J, Wang L, Zhang W, Ma J, Zhang X, Putnis CV. Organically-bound silicon enhances resistance to enzymatic degradation and nanomechanical properties of rice plant cell walls. Carbohydr Polym 2021; 266:118057. [PMID: 34044915 DOI: 10.1016/j.carbpol.2021.118057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 12/31/2022]
Abstract
Plant cell walls exhibit excellent mechanical properties, which form the structural basis for sustainable bioresources and multifunctional nanocelluloses. The wall nanomechanical properties of living cells through covalent modifications of hybrid inorganic elements, such as silicon, may confer significant influence on local mechano-response and enzymatic degradation. Here, we present a combination of ex situ measurements of enzyme-released oligosaccharide fragments using MALDI-TOF MS and in situ atomic force microscopy (AFM) imaging through PeakForce quantitative nanomechanical mapping of tip-functionalized single-molecule enzyme-polysaccharide substrate recognition and the nanoscale dissolution kinetics of individual cellulose microfibrils of living rice (Oryza sativa) cells following silicate cross-linking of cell wall xyloglucan. We find that xyloglucan-bound silicon enhances the resistance to degradation by cellulase and improves the wall nanomechanical properties in the elastic modulus at the single-cell level. The findings establish a direct link between an inorganic element of silicon and the nanoscale architecture of plant cell wall materials for sustainable utilization.
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Affiliation(s)
- Junbao Pu
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jie Ma
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiuqing Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149, Münster, Germany; School of Molecular and Life Science, Curtin University, 6845, Perth, Australia
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Abstract
Organo–mineral interactions have long been the focus in the fields of biomineralization and geomineralization, since such interactions not only modulate the dynamics of crystal nucleation and growth but may also change crystal phases, morphologies, and structures.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment
- Huazhong Agricultural University
- Wuhan 430070
- China
- Department of Plant and Environmental Sciences
| | - Wenjun Zhang
- College of Resources and Environment
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Lijun Wang
- College of Resources and Environment
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Christine V. Putnis
- Institut für Mineralogie
- University of Münster
- 48149 Münster
- Germany
- School of Molecular and Life Science
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9
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Zhang J, Zhang W, Putnis CV, Wang L. Modulation of the calcium oxalate dihydrate to calcium oxalate monohydrate phase transition with citrate and zinc ions. CrystEngComm 2021. [DOI: 10.1039/d1ce01336j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Higher concentrations of Ca2+ and Ox2− can form COD which then transforms to COM. Citrate forms a protective layer to inhibit COD transition; whereas Zn2+ substitutes Ca2+ sites to generate a stable COD structure that retards COM formation.
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Affiliation(s)
- Jing Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Christine V. Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- School of Molecular and Life Science, Curtin University, 6845 Perth, Australia
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China
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10
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Abstract
Chemical reactions at the mineral-solution interface control important interfacial processes, such as geochemical element cycling, nutrient recovery from eutrophicated waters, sequestration of toxic contaminants, and geological carbon storage by mineral carbonation. By time-resolved in situ imaging of nanoscale mineral interfacial reactions, it is possible to clarify the mechanisms governing mineral-fluid reactions.In this Account, we present a concise summary of this topic that addresses a current challenge at the frontier of understanding mineral interfaces and their importance to a wide range of mineral re-equilibration processes in the presence of a fluid aqueous phase. We have used real-time nanoscale imaging of liquid-cell atomic force microscopy (AFM) to observe the in situ coupling of the dissolution-precipitation process, whereby the dissolution of a parent mineral phase is coupled at mineral interfaces with the precipitation of another product phase, chemically different from the parent. These nanoscale observations allow for the identification of dissolution and growth rates through systematically investigating various minerals, including calcite (CaCO3), siderite (FeCO3), cerussite (PbCO3), magnesite (MgCO3), dolomite (CaMg(CO3)2), brushite (CaHPO4·2H2O), brucite (Mg(OH)2), portlandite (Ca(OH)2), and goethite (α-FeOOH), in various reacting aqueous fluids containing solution species, such as arsenic, phosphate, organo- or pyrophosphate, CO2, selenium, lead, cadmium, iron, chromium, and antimony. We detected the in situ replacement of these parent mineral phases by product phases, identified through a variety of analytical methods such as Raman spectroscopy, high-resolution transmission electron microscopy, and various X-ray techniques, as well as modeling by geochemical simulation using PHREEQC. As a consequence of the coupled processes, sequestration of toxic elements and hazardous species and inorganic and organic carbon, and limiting or promoting recovery of nutrients can be achieved at nano- and macroscopic scales.We also used in situ AFM to quantitatively measure the retreat rates of molecular steps and directly observe the morphology changes of dissolution etch pits on calcium phosphates in organic acid solutions present in most rhizosphere environments. By molecular modeling using density functional theory (DFT), we explain the origin of dissolution etch pit evolution through specific stereochemistry and molecular recognition and provide an energetic basis by calculating the binding energies of chemical functionalities on organic acids to direction-specific steps on mineral surfaces. In addition, we further quantified precipitation kinetics of calcium phosphates (Ca-P's) on typical mineral surfaces at the nanoscale in environmentally relevant solutions with various organic molecules, by measurements obtained from sequential images obtained by liquid-cell AFM. In situ dynamic force spectroscopy (DFS) was used to determine binding energies of single-molecules with different chemical functionalities found in natural organic matter at mineral-fluid interfaces. Quantifying molecular organo-mineral bonding or binding energies mechanistically explains phosphate precipitation and transformation. From DFS measurements, molecular-scale interactions of mineral-natural organic matter (DNA, proteins, and polysaccharides) associations were determined. With this powerful tool, single-molecule determinations of polysaccharide-amorphous iron oxide or hematite interactions provided the mechanistic origin of the phase- or facet-dependent adsorption. These systematic investigations and findings significantly contribute to a more quantitative prediction of the fate of nutrients and contaminants, chemical element cycling, and potential geological carbon capture and nuclear waste storage in aqueous environments.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V. Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- School of Molecular and Life Science, Curtin University, Perth, WA 6845, Australia
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11
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Zhang J, Wang L, Zhang W, Putnis CV. Phosphorylated/Nonphosphorylated Motifs in Amelotin Turn Off/On the Acidic Amorphous Calcium Phosphate-to-Apatite Phase Transformation. Langmuir 2020; 36:2102-2109. [PMID: 32036670 DOI: 10.1021/acs.langmuir.9b02735] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Amelotin (AMTN) as a matrix protein exerts a direct effect on biomineralization by modulating apatite (HAP) formation during the dental enamel maturation stage through the specific interaction of a potentially phosphorylated Ser-Ser-Glu-Glu-Leu (SSEEL) peptide fragment with calcium phosphate (Ca-P) surfaces. However, the roles of (non)phosphorylation of this evolutionarily conserved subdomain within AMTN remain poorly understood. Here, we show, by time-resolved atomic force microscopy (AFM) imaging of in situ HAP crystallization via the HPO42--rich amorphous calcium phosphate (acidic ACP), the on/off switching of the phase transformation process through a nonphosphorylation-to-phosphorylation transition of the SSEEL motif. Using high-resolution transmission electron microscopy (HRTEM), we observed that the acidic ACP phase is stabilized by the phosphorylated SSEEL motif, delaying its transformation to HAP, whereas the nonphosphorylated counterpart promotes HAP formation by accelerating the dissolution-recrystallization of the acidic ACP substrate. Dynamic force spectroscopy measurements demonstrate greater binding energies of nonphosphorylated SSEEL to the acidic ACP substrate by the formation of molecular peptide-ACP bonding, explaining the enhanced dissolution of the acidic ACP substrate by stronger complexion with surface Ca2+ ions. Our findings demonstrate direct evidence for the switching role of (non)phosphorylation of an evolutionarily conserved subdomain within AMTN in controlling the phase transition of growing enamel and designing tissue regeneration biomaterials.
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Affiliation(s)
- Jing Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- Department of Chemistry, Curtin University, Perth 6845, Australia
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Ge X, Wang L, Zhang W, Putnis CV. Molecular Understanding of Humic Acid-Limited Phosphate Precipitation and Transformation. Environ Sci Technol 2020; 54:207-215. [PMID: 31822060 DOI: 10.1021/acs.est.9b05145] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Phosphorus (P) availability is widely assumed to be limited by the formation of metal (Ca, Fe, or Al) phosphate precipitates that are modulated by soil organic matter (SOM), but the SOM-precipitate interactions remain uncertain because of their environmental complexities. Here, we present a model system by quantifying the in situ nanoscale nucleation kinetics of calcium phosphates (Ca-Ps) on mica in environmentally relevant aqueous solutions by liquid-cell atomic force microscopy. We find that Ca-P precipitate formation is slower when humic acid (HA) concentration is higher. High-resolution transmission electron microscopy observations demonstrate that HA strongly stabilizes amorphous calcium phosphate (ACP), delaying its subsequent transformation to thermodynamically more stable phases. Consistent with the formation of molecular organo-mineral bonding, dynamic force spectroscopy measurements display larger binding energies of organic ligands with certain chemical functionalities on HA to the initially formed ACP than to mica that are responsible for stabilization of ACP through stronger HA-ACP interactions. Our results provide direct evidence for the proposed importance of SOM in inhibiting Ca-P precipitation/transformation. We suggest that similar studies of binding strength in SOM-Fe/Al-P may reveal how both organic matter and metal ions control P availability and fate, and thus the eventual P management for agronomical and environmental sustainability.
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Affiliation(s)
- Xinfei Ge
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Wenjun Zhang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, Münster 48149, Germany
- Department of Chemistry, Curtin University, Perth 6845, Australia
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13
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Zhai H, Wang L, Putnis CV. Molecular-Scale Investigations Reveal Noncovalent Bonding Underlying the Adsorption of Environmental DNA on Mica. Environ Sci Technol 2019; 53:11251-11259. [PMID: 31478650 DOI: 10.1021/acs.est.9b04064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Mineral-soil organic matter (SOM including DNA, proteins, and polysaccharides) associations formed through various interactions, play a key role in regulating long-term SOM preservation. The mechanisms underlying DNA-mineral and DNA-protein/polysaccharide interactions at nanometer and molecular scales in environmentally relevant solutions remain uncertain. Here, we present a model mineral-SOM system consisting of mineral (mica)-nucleic acid (environmental DNA, eDNA)/protein (bovine serum albumin)/polysaccharide (alginate), and combine atomic force microscopy (AFM)-based dynamic force spectroscopy and PeakForce quantitative nanomechanical mapping using DNA-decorated tips. Single-molecule binding and adhesion force of eDNA to mineral and to mineral adsorbed by protein/polysaccharide reveal the noncovalent bonds and that systematically changing ion compositions, ionic strength, and pH result in significant differences in organic-organic and organic-mineral binding energies. Consistent with the bond-strength measurements, protein, rather than polysaccharide, promotes mineral-bound DNA molecules by ex situ AFM deposition observations in relatively high concentrations of divalent cation-containing acidic solutions. These molecular-scale determinations and nanoscale observations should substantially improve our understanding of how environmental factors influence the organic-mineral interfacial interactions through the synergy of collective noncovalent and/or covalent bonds in mineral-organic associations.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
- Department of Chemistry , Curtin University , Perth 6845 , Australia
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14
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Abstract
Global soil carbon cycling plays a key role in regulating and stabilizing the earth's climate change because of soils with amounts of carbon at least three times greater than those of other ecological systems. Soil minerals have also been shown to underlie the persistence of soil organic matter (SOM) through both adsorption and occlusion, but the microscopic mechanisms that control the latter process are poorly understood. Here, using time-resolved in situ atomic force microscopy (AFM) to observe how calcite, a representative mineral in alkaline soils, interacts with humic substances, we show that following adsorption, humic substances are gradually occluded by the advancing steps of spirals on the calcite (1014) face grown in relatively high supersaturated solutions, through the embedment, compression, and closure of humic substance particles into cavities. This occlusion progress is inhibited by phytate at high concentrations (10-100 μM) due to the formation of phytate-Ca precipitates on step edges to prevent the step advancement, whereas phytate at relatively low concentrations (≤1 μM) and oxalate at high concentrations (100 μM) have little effect on this process. These in situ observations may provide new insights into the organo-mineral interaction, resulting in the incorporation of humic substances into minerals with a longer storage time to delay degradation in soils. This will improve our understanding of carbon cycling and immobilization in soil ecological systems.
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Affiliation(s)
- Jialin Chi
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Wenjun Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
- Department of Chemistry , Curtin University , Perth 6845 , Australia
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15
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Abstract
The majority of human kidney stones are composed of multiple calcium oxalate crystals with variable amounts of brushite [dicalcium phosphate dihydrate (DCPD)] and hydroxyapatite (HAP) as a nucleus, in which fluid-mediated dissolution and reprecipitation may result in the phase transformation of DCPD to HAP. However, the underlying mechanisms of the phase transition and its modulation by natural inhibitors, such as osteopontin (OPN) proteins, remain poorly understood. Here, the in vitro formation of new phases on the DCPD (010) surface is observed in situ using atomic force microscopy in a simulated hypercalciuria milieu. We demonstrate the presence of an acidic amorphous calcium phosphate (ACP) phase with a characteristic Raman band of ν1HPO42- and the octacalcium phosphate (OCP)-like phase during the transformation process. High-resolution transmission electron microscopy analyses also confirm the existence of OCP and HAP within an amorphous matrix phase. In support of clinical observations, we further demonstrate the inhibitory effect of OPN peptide segments on the dissolution of DCPD and reprecipitation of acidic ACP. The definition of respective roles of DCPD and OPN thereby provides insights into the control of nucleus formation and subsequent inhibition of pathological mineralization.
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Affiliation(s)
- Jing Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , Münster 48149 , Germany.,Department of Chemistry , Curtin University , Perth 6845 , Australia
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16
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Abstract
Modulation of mineralization and demineralization of calcium phosphates (Ca-Ps) with organic macromolecules is a critical process which prevents human kidney stone disease. As a long unbranched polysaccharide of urinary glycosaminoglycans, chondroitin 4-sulfate (Ch4S) has been shown to play an essential role in inhibiting the formation of kidney stones. However, the mechanism of the role of Ch4S remains poorly understood. Here, we used in situ atomic force microscopy to observe the growth and dissolution of spirals on brushite (CaHPO4·2H2O) (010) surfaces. The results show that Ch4S preferentially inhibits the [101]Cc step growth/dissolution by step pinning. This step-specific effect appears to be related to specific binding of Ch4S to Ca sites, as the observed inhibition is not seen in other crystallographic directions where there are fewer Ca terminations. Moreover, Ch4S promotes an increase in the terrace width of [101̅]Cc by the modification of the interfacial energies of the step edge. These in vitro direct observations of Ch4S modulating brushite mineralization and demineralization reveal a dual control of both step kinetics and interfacial energy.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany.,Department of Chemistry , Curtin University , Perth 6845 , Australia
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17
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Zhai H, Wang L, Hövelmann J, Qin L, Zhang W, Putnis CV. Humic Acids Limit the Precipitation of Cadmium and Arsenate at the Brushite-Fluid Interface. Environ Sci Technol 2019; 53:194-202. [PMID: 30516375 DOI: 10.1021/acs.est.8b05584] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Bioavailability and mobility of cadmium (Cd2+) and arsenate (As5+) in soils can be effectively lowered through the dissolution of brushite (dicalcium phosphate dihydrate, CaHPO4·2H2O) coupled with the precipitation of a more stable mineral phase containing both Cd and As. Due to the ubiquitous presence of humic acid (HA) in soil environments, it is more complex to predict the fate of dissolved Cd and As during such sequestration. Here, we used in situ atomic force microscopy (AFM) to image the kinetics of simultaneous precipitation of Cd and As at the brushite-fluid interface in the presence of HA. Results show that HA inhibits the formation of both amorphous and crystalline Cd(5- x)Ca x(PO4)(3- y)(AsO4) y(OH) on the (010) face of brushite. A combination of X-ray photoelectron spectroscopy (XPS) and real-time surface-enhanced Raman spectroscopy (SERS) reveals that part of As5+ reduction into As3+ with HA and [HA-Cd] complexation occurs, modulating the concentrations of free Cd2+ and As5+ ions to inhibit subsequent precipitation of a Cd(5- x)Ca x(PO4)(3- y)(AsO4) y(OH) phase on the dissolving brushite surface. A combination of AFM imaging, SERS analyses, and PhreeqC simulations suggests that environmentally relevant humic substances can limit the precipitation of Cd and As at mineral surfaces through a mechanism of oxidation/reduction and aqueous/surface complexation. This may exacerbate the transportation of these contaminants into waters by subsurface fluid flow, and research attempts to weaken the negative effect of HA are needed.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Jörn Hövelmann
- GFZ German Research Centre for Geosciences, Telegrafenberg, 14473 Potsdam , Germany
| | - Lihong Qin
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Wenjun Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
- Department of Chemistry , Curtin University , Perth , Western Australia 6845 , Australia
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18
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Zhai H, Qin L, Zhang W, Putnis CV, Wang L. Dynamics and Molecular Mechanism of Phosphate Binding to a Biomimetic Hexapeptide. Environ Sci Technol 2018; 52:10472-10479. [PMID: 30138561 DOI: 10.1021/acs.est.8b03062] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Phosphorus (P) recovery from wastewater is essential for sustainable P management. A biomimetic hexapeptide (SGAGKT) has been demonstrated to bind inorganic P in P-rich environments, however the dynamics and molecular mechanisms of P-binding to the hexapeptide still remain largely unknown. We used dynamic force spectroscopy (DFS) to directly distinguish the P-unbound and P-bound SGAGKT adsorbed to a mica (001) surface by measuring the single-molecule binding free energy (Δ Gb). Using atomic force microscopy (AFM) to determine real-time step retreat velocities of triangular etch pits formed at the nanoscale on the dissolving (010) face of brushite (CaHPO4·2H2O) in the presence of SGAGKT, we observed that SGAGKT peptides promoted in situ dissolution through an enhanced P-binding driven by hydrogen bonds in a P-loop being capable of discriminating phosphate over arsenate, concomitantly forming a thermodynamically favored SGAGKT-HPO42- complexation at pH 8.0 and relatively low ionic strength, consistent with the DFS and isothermal titration calorimetry (ITC) determinations. The findings reveal the thermodynamic and kinetic basis for binding of phosphate to SGAGKT and provide direct evidence for phosphate discrimination in phosphate/arsenate-rich environments.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Lihong Qin
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Wenjun Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
- Department of Chemistry , Curtin University , Perth , WA6845 , Australia
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , China
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19
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Zhai H, Wang L, Qin L, Zhang W, Putnis CV, Putnis A. Direct Observation of Simultaneous Immobilization of Cadmium and Arsenate at the Brushite-Fluid Interface. Environ Sci Technol 2018; 52:3493-3502. [PMID: 29488373 DOI: 10.1021/acs.est.7b06479] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cadmium (Cd2+) and Arsenate (As5+) are the main toxic elements in soil environments and are easily taken up by plants. Unraveling the kinetics of the adsorption and subsequent precipitation/immobilization on mineral surfaces is of considerable importance for predicting the fate of these dissolved species in soils. Here we used in situ atomic force microscopy (AFM) to image the dissolution on the (010) face of brushite (dicalcium phosphate dihydrate, CaHPO4·2H2O) in CdCl2- or Na2HAsO4-bearing solutions over a broad pH and concentration range. During the initial dissolution processes, we observed that Cd or As adsorbed on step edges to modify the morphology of etch pits from the normal triangular shape to a four-sided trapezium. Following extended reaction times, the respective precipitates were formed on brushite through a coupled dissolution-precipitation mechanism. In the presence of both CdCl2 and Na2HAsO4 in reaction solutions at pH 8.0, high-resolution transmission electron microscopy (HRTEM) showed a coexistence of both amorphous and crystalline phases, i.e., a mixed precipitate of amorphous and crystalline Cd(5- x)Ca x(AsO4)(3- y)(PO4) yOH phases was detected. These direct dynamic observations of the transformation of adsorbed species to surface precipitates may improve the mechanistic understanding of the calcium phosphate mineral interface-induced simultaneous immobilization of both Cd and As and subsequent sequestration in diverse soils.
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Affiliation(s)
- Hang Zhai
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Lijun Wang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Lihong Qin
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Wenjun Zhang
- College of Resources and Environment , Huazhong Agricultural University , Wuhan 430070 , P. R. China
| | - Christine V Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
| | - Andrew Putnis
- Institut für Mineralogie , University of Münster , 48149 Münster , Germany
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20
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Li M, Zhang J, Wang L, Wang B, Putnis CV. Mechanisms of Modulation of Calcium Phosphate Pathological Mineralization by Mobile and Immobile Small-Molecule Inhibitors. J Phys Chem B 2018; 122:1580-1587. [PMID: 29346735 DOI: 10.1021/acs.jpcb.7b10956] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Potential pathways for inhibiting crystal growth are via either disrupting local microenvironments surrounding crystal-solution interfaces or physically blocking solute molecule attachment. However, the actual mode of inhibition may be more complicated due to the characteristic time scale for the inhibitor adsorption and relaxation to a well-bound state at crystal surfaces. Here we demonstrate the role of citrate (CA) and hydroxycitrate (HCA) in brushite (DCPD, CaHPO4·2H2O) crystallization over a broad range of both inhibitor concentrations and supersaturations by in situ atomic force microscopy (AFM). We observed that both inhibitors exhibit two distinct actions: control of surface crystallization by the decrease of step density at high supersaturations and the decrease of the [1̅00]Cc step velocity at high inhibitor concentration and low supersaturation. The switching of the two distinct modes depends on the terrace lifetime, and the slow kinetics along the [1̅00]Cc step direction provides specific sites for the newly formed dislocations. Molecular modeling shows the strong HCA-crystal interaction by molecular recognition, explaining the AFM observations for the formation of new steps and surface dissolution along the [101]Cc direction due to the introduction of strong localized strain in the crystal lattice. These direct observations highlight the importance of the inhibitor coverage on mineral surfaces, as well as the solution supersaturation in predicting the inhibition efficacy, and reveal an improved understanding of inhibition of calcium phosphate biomineralization, with clinical implications for the full therapeutic potential of small-molecule inhibitors for kidney stone disease.
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Affiliation(s)
- Meng Li
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Jing Zhang
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Baoshan Wang
- College of Chemistry and Molecular Sciences, Wuhan University , Wuhan 430072, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany.,Department of Chemistry, Curtin University , Perth, Western Australia 6845, Australia
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21
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Renard F, Putnis CV, Montes-Hernandez G, King HE, Breedveld GD, Okkenhaug G. Sequestration of Antimony on Calcite Observed by Time-Resolved Nanoscale Imaging. Environ Sci Technol 2018; 52:107-113. [PMID: 29210275 DOI: 10.1021/acs.est.7b04727] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Antimony, which has damaging effects on the human body and the ecosystem, can be released into soils, ground-, and surface waters either from ore minerals that weather in near surface environments, or due to anthropogenic releases from waste rich in antimony, a component used in batteries, electronics, ammunitions, plastics, and many other industrial applications. Here, we show that dissolved Sb can interact with calcite, a widespread carbonate mineral, through a coupled dissolution-precipitation mechanism. The process is imaged in situ, at room temperature, at the nanometer scale by using an atomic force microscope equipped with a flow-through cell. Time-resolved imaging allowed following the coupled process of calcite dissolution, nucleation of precipitates at the calcite surface and growth of these precipitates. Sb(V) forms a precipitate, whereas Sb(III) needs to be oxidized to Sb(V) before being incorporated in the new phase. Scanning-electron microscopy and Raman spectroscopy allowed identification of the precipitates as two different calcium-antimony phases (Ca2Sb2O7). This coupled dissolution-precipitation process that occurs in a boundary layer at the calcite surface can sequester Sb as a solid phase on calcite, which has environmental implications as it may reduce the mobility of this hazardous compound in soils and groundwaters.
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Affiliation(s)
- François Renard
- Department of Geosciences, Physics of Geological Processes, University of Oslo , Oslo, Norway
- Univ. Grenoble Alpes, CNRS, ISTerre , 38000, Grenoble, France
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster , Corrensstrasse 24, 48149 Münster, Germany
- The Institute for Geoscience Research (TIGeR), Department of Chemistry, Curtin University , Perth, 6845, Australia
| | | | - Helen E King
- Department of Earth Sciences, Utrecht University Budapestlaan 4 , 3584 CD Utrecht, The Netherlands
| | - Gijs D Breedveld
- Department of Geosciences, Physics of Geological Processes, University of Oslo , Oslo, Norway
- Norwegian Geotechnical Institute , box 3930, Ullevål Stadion, 0806 Oslo, Norway
| | - Gudny Okkenhaug
- Norwegian Geotechnical Institute , box 3930, Ullevål Stadion, 0806 Oslo, Norway
- Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management , box 5003, 1432 Ås, Norway
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22
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Abstract
This review highlights in situ atomic force microscopy observations of the classical and nonclassical surface growth dynamics of calcium orthophosphates.
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Affiliation(s)
- Meng Li
- College of Resources and Environment
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Lijun Wang
- College of Resources and Environment
- Huazhong Agricultural University
- Wuhan 430070
- China
| | - Christine V. Putnis
- Institut für Mineralogie
- University of Münster
- 48149 Münster
- Germany
- Department of Chemistry
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Affiliation(s)
- Meng Li
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V. Putnis
- Institut
für Mineralogie, University of Münster, 48149 Münster, Germany
- Department of Chemistry, Curtin University, Perth, Western Australia 6845, Australia
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24
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King HE, Plümper O, Putnis CV, O’Neill HSC, Klemme S, Putnis A. Mineral Surface Rearrangement at High Temperatures: Implications for Extraterrestrial Mineral Grain Reactivity. ACS Earth Space Chem 2017; 1:113-121. [PMID: 28470055 PMCID: PMC5407656 DOI: 10.1021/acsearthspacechem.6b00016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/06/2017] [Accepted: 03/06/2017] [Indexed: 06/07/2023]
Abstract
Mineral surfaces play a critical role in the solar nebula as a catalytic surface for chemical reactions and potentially acted as a source of water during Earth's accretion by the adsorption of water molecules to the surface of interplanetary dust particles. However, nothing is known about how mineral surfaces respond to short-lived thermal fluctuations that are below the melting temperature of the mineral. Here we show that mineral surfaces react and rearrange within minutes to changes in their local environment despite being far below their melting temperature. Polished surfaces of the rock and planetary dust-forming silicate mineral olivine ((Mg,Fe)2SiO4) show significant surface reorganization textures upon rapid heating resulting in surface features up to 40 nm in height observed after annealing at 1200 °C. Thus, high-temperature fluctuations should provide new and highly reactive sites for chemical reactions on nebula mineral particles. Our results also may help to explain discrepancies between short and long diffusion profiles in experiments where diffusion length scales are of the order of 100 nm or less.
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Affiliation(s)
- Helen E. King
- Institut
für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany
- Department
of Geology and Geophysics, Yale University, 210 Whitney Avenue, New Haven, Connecticut 06511, United States
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Oliver Plümper
- Department
of Earth Sciences, Utrecht University, Budapestlaan 4, 3584 CD Utrecht, The Netherlands
| | - Christine V. Putnis
- Institut
für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany
- Department
of Chemistry, Curtin University, Kent Street, Perth 6845, Australia
| | - Hugh St. C. O’Neill
- Research
School of Earth Sciences, The Australian
National University, Canberra, ACT 2601, Australia
| | - Stephan Klemme
- Institut
für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany
| | - Andrew Putnis
- Institut
für Mineralogie, University of Münster, Corrensstrasse 24, 48149 Münster, Germany
- The
Institute for Geoscience Research (TIGeR), Curtin University, P.O. Box U1987, Perth 6845, Australia
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25
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Wang L, Putnis CV, King HE, Hövelmann J, Ruiz-Agudo E, Putnis A. Imaging Organophosphate and Pyrophosphate Sequestration on Brucite by in Situ Atomic Force Microscopy. Environ Sci Technol 2017; 51:328-336. [PMID: 27983815 DOI: 10.1021/acs.est.6b05456] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In order to evaluate the organic phosphorus (OP) and pyrophosphate (PyroP) cycle and their fate in the environment, it is critical to understand the effects of mineral interfaces on the reactivity of adsorption and precipitation of OP and PyroP. Here, in situ atomic force microscopy (AFM) is used to directly observe the kinetics of coupled dissolution-precipitation on cleaved (001) surfaces of brucite [Mg(OH)2] in the presence of phytate, glucose-6-phosphate (G6P) and pyrophosphate, respectively. AFM results show that the relative order of contribution to mineral surface adsorption and precipitation is phytate > pyrophosphate > G6P under the same solution conditions and can be quantified by the induction time of OP/PyroP-Mg nucleation in a boundary layer at the brucite-water interface. Calculations of solution speciation during brucite dissolution in the presence of phytate or pyrophosphate at acidic pH conditions show that the solutions may reach supersaturation with respect to Mg5H2Phytate.6H2O as a Mg-phytate phase or Mg2P2O7 as a Mg-pyrophosphate phase that becomes thermodynamically stable before equilibrium with brucite is reached. This is consistent with AFM dynamic observations for the new phase formations on brucite. Direct nanoscale observations of the transformation of adsorption/complexation-surface precipitation, combined with spectroscopic characterizations and species simulations may improve the mechanistic understanding of organophosphate and pyrophosphate sequestration by mineral replacement reactions through a mechanism of coupled dissolution-precipitation occurring at mineral-solution interfaces in the environment.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany
- Department of Chemistry, Curtin University , Perth, Western Australia 6845, Australia
| | - Helen E King
- Department of Earth Sciences, Utrecht University , 3584 CD Utrecht, The Netherlands
| | - Jörn Hövelmann
- Interface-Geochemistry, Geoforschungszentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany
| | - Encarnación Ruiz-Agudo
- Department of Mineralogy and Petrology, University of Granada , Fuentenueva s/n, Grenada 18071, Spain
| | - Andrew Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany
- The Institute for Geoscience Research (TIGeR), Curtin University , Perth, Western Australia 6102, Australia
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Di Lorenzo F, Burgos-Cara A, Ruiz-Agudo E, Putnis CV, Prieto M. Effect of ferrous iron on the nucleation and growth of CaCO3in slightly basic aqueous solutions. CrystEngComm 2017. [DOI: 10.1039/c6ce02290a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hövelmann J, Putnis CV. In Situ Nanoscale Imaging of Struvite Formation during the Dissolution of Natural Brucite: Implications for Phosphorus Recovery from Wastewaters. Environ Sci Technol 2016; 50:13032-13041. [PMID: 27934285 DOI: 10.1021/acs.est.6b04623] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
As phosphorus (P) resources are diminishing, the recovery of this essential nutrient from wastewaters becomes an increasingly interesting option. P-recovery through the controlled crystallization of struvite (MgNH4PO4·6H2O), a potential slow-release fertilizer, is highly attractive, but costly if large amounts of Mg have to be added. In this context, natural Mg-minerals like brucite (Mg(OH)2) could provide more cost-effective Mg-sources compared to high-grade Mg-compounds such as MgCl2. Here we used in situ atomic force microscopy (AFM) to study the interactions of ammonium phosphate solutions with brucite (001) cleavage surfaces. Brucite dissolution was strongly enhanced in the presence of H2PO4- ions, most likely due to the formation of negatively charged surface complexes. Simultaneously with brucite dissolution, we directly observed the formation of a new phase that was identified as struvite by Raman spectroscopy. Our results suggest that brucite dissolution and struvite precipitation were coupled at the mineral-fluid interface within a thin fluid boundary layer. An interpretation is proposed where the heterogeneous nucleation and growth of struvite occurs via a particle-mediated process involving the formation of primary nanoparticles, followed by their continuous aggregation, fusion and possible transformation to crystalline struvite. These observations have implications for the feasibility of using brucite in phosphorus recovery processes.
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Affiliation(s)
- Jörn Hövelmann
- German Research Centre for Geosciences (GFZ), Interface Geochemistry, 14473 Potsdam, Germany
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany
- The Institute for Geoscience Research (TIGeR), Department of Chemistry, Curtin University , Perth 6845, Australia
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Wang L, Qin L, Putnis CV, Ruiz-Agudo E, King HE, Putnis A. Visualizing Organophosphate Precipitation at the Calcite-Water Interface by in Situ Atomic-Force Microscopy. Environ Sci Technol 2016; 50:259-268. [PMID: 26636475 DOI: 10.1021/acs.est.5b05214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Esters of phosphoric acid constitute a large fraction of the total organic phosphorus (OP) in the soil environment and, thus, play an important role in the global phosphorus cycle. These esters, such as glucose-6-phosphate (G6P), exhibit unusual reactivity toward various mineral particles in soils, especially those containing calcite. Many important processes of OP transformation, including adsorption, hydrolysis, and precipitation, occur primarily at mineral-fluid interfaces, which ultimately governs the fate of organophosphates in the environment. However, little is known about the kinetics of specific mineral-surface-induced adsorption and precipitation of organophosphates. Here, by using in situ atomic-force microscopy (AFM) to visualize the dissolution of calcite (1014) faces, we show that the presence of G6P results in morphology changes of etch pits from the typical rhombohedral to a fan-shaped form. This can be explained by a site-selective mechanism of G6P-calcite surface interactions that stabilize the energetically unfavorable (0001) or (0112) faces through step-specific adsorption of G6P. Continuous dissolution at calcite (1014)-water interfaces caused a boundary layer at the calcite-water interface to become supersaturated with respect to a G6P-Ca phase that then drives the nucleation and growth of a G6P-Ca precipitate. Furthermore, after the introduction of the enzyme alkaline phosphatase (AP), the precipitates were observed to contain a mixture of components associated with G6P-Ca, amorphous calcium phosphate (ACP)-hydroxyapatite (HAP) and dicalcium phosphate dihydrate (DCPD). These direct dynamic observations of the transformation of adsorption- and complexation-surface precipitation and enzyme-mediated pathways may improve the mechanistic understanding of the mineral-interface-induced organophosphate sequestration in the soil environment.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Lihong Qin
- College of Resources and Environment, Huazhong Agricultural University , Wuhan 430070, China
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany
- Nanochemistry Research Institute, Department of Chemistry, Curtin University , Perth, Western Australia 6845, Australia
| | - Encarnación Ruiz-Agudo
- Department of Mineralogy and Petrology, University of Granada , Fuentenueva s/n, Granada 18071, Spain
| | - Helen E King
- Department of Earth Sciences, Utrecht University , 3584 CD Utrecht, The Netherlands
| | - Andrew Putnis
- Institut für Mineralogie, University of Münster , 48149 Münster, Germany
- The Institute for Geoscience Research (TIGeR), Curtin University , Perth, Western Australia 6102, Australia
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Ruiz-Agudo C, Ruiz-Agudo E, Burgos-Cara A, Putnis CV, Ibáñez-Velasco A, Rodriguez-Navarro C, Putnis A. Exploring the effect of poly(acrylic acid) on pre- and post-nucleation BaSO4species: new insights into the mechanisms of crystallization control by polyelectrolytes. CrystEngComm 2016. [DOI: 10.1039/c6ce00142d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ruiz-Agudo C, Putnis CV, Ibañez-Velasco A, Ruiz-Agudo E, Putnis A. A potentiometric study of the performance of a commercial copolymer in the precipitation of scale forming minerals. CrystEngComm 2016. [DOI: 10.1039/c6ce00537c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Di Tommaso D, Ruiz-Agudo E, de Leeuw NH, Putnis A, Putnis CV. Modelling the effects of salt solutions on the hydration of calcium ions. Phys Chem Chem Phys 2015; 16:7772-85. [PMID: 24643252 DOI: 10.1039/c3cp54923b] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Classical molecular dynamics simulations of several aqueous alkali halide salt solutions have been used to determine the effect of electrolytes on the structure of water and the hydration properties of calcium ions. Compared with the simulations of Ca(2+) ions in pure liquid water, the frequency of water exchange in the first hydration shell of calcium, which is a fundamental process in controlling the reactivity of calcium(ii) aqua-ions, is drastically reduced in the presence of other electrolytes in solution. The strong stabilization of the hydration shell of Ca(2+) occurs not only when the halide anions are directly coordinated to calcium, but also when the alkali and halide ions are placed at or outside the second coordination shell of Ca(2+), suggesting that the reactivity of the first solvation shell of the calcium ion can be influenced by the specific affinity of other ions in solution for the water molecules coordinated to Ca(2+). Analysis of the hydrogen-bonded structure of water in the vicinity of the calcium ion shows that the average number of hydrogen bonds per water molecules, which is 1.8 in pure liquid water, decreases as the concentration of alkali-halide salts in solution increases, and that the temporal fluctuations of hydrogen bonds are significantly larger than those obtained for Ca(2+) in pure liquid water. This effect has been explained in terms of the dynamics of reorganization of the O-H···X(-) (X = F, Cl and Br) hydrogen bond. This work shows the importance of solution composition in determining the hydrogen-bonding network and ligand-exchange dynamics around metal ions, both in solution and at the mineral-water interfaces, which in turn has implications for interactions occurring at the mineral-water interface, ultimately controlling the mobilization of ions in the environment as well as in industrial processes.
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Affiliation(s)
- Devis Di Tommaso
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
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Wang L, Putnis CV, Ruiz-Agudo E, Hövelmann J, Putnis A. In situ imaging of interfacial precipitation of phosphate on Goethite. Environ Sci Technol 2015; 49:4184-4192. [PMID: 25763812 DOI: 10.1021/acs.est.5b00312] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Adsorption and subsequent immobilization of orthophosphate on iron oxides is of considerable importance in soil fertility and eutrophication studies. Here, in situ atomic force microscopy (AFM) has been used to probe the interaction of phosphate-bearing solutions with goethite, α-FeOOH, (010) cleavage surfaces. During the dissolution of goethite we observed simultaneous nucleation of nanoparticles (1.0-3.0 nm in height) of iron phosphate (Fe-P) phases at the earliest nucleation stages, subsequent aggregation to form secondary particles (about 6.0 nm in height) and layered precipitates under various pH values and ionic strengths relevant to acid soil solution conditions. The heterogeneous nucleation rates of Fe-P precipitates at phosphate concentrations ranging from 5.0 to 50.0 mM were quantitatively defined. Enhanced goethite dissolution in the presence of high concentration NaCl or AlCl3 leads to a rapid increase in Fe-P nucleation rates, whereas low concentration MgCl2 inhibits goethite dissolution, this in turn influences Fe-P nucleation. Moreover, kinetic data analyses show that low concentrations of citrate caused an increase in the nucleation rate of Fe-P phases. However, at higher concentrations of citrate, nucleation acceleration was reversed with much longer induction times to form Fe-P nuclei. These in situ observations may improve the mechanistic understanding of processes resulting in phosphate immobilization by goethite-rich acid soils in the presence of various inorganic and organic additive molecules.
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Affiliation(s)
- Lijun Wang
- †College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
| | - Christine V Putnis
- ‡Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- §Department of Chemistry, Curtin University, P.O. Box U1987, Perth, Washington 6845, Australia
| | | | - Jörn Hövelmann
- ‡Institut für Mineralogie, University of Münster, 48149 Münster, Germany
| | - Andrew Putnis
- ‡Institut für Mineralogie, University of Münster, 48149 Münster, Germany
- ⊥The Institute for Geoscience Research (TIGeR), Curtin University, Perth, Washington 6102, Australia
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Offeddu FG, Cama J, Soler JM, Putnis CV. Direct nanoscale observations of the coupled dissolution of calcite and dolomite and the precipitation of gypsum. Beilstein J Nanotechnol 2014; 5:1245-1253. [PMID: 25161860 PMCID: PMC4142853 DOI: 10.3762/bjnano.5.138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 07/21/2014] [Indexed: 06/03/2023]
Abstract
In-situ atomic force microscopy (AFM) experiments were performed to study the overall process of dissolution of common carbonate minerals (calcite and dolomite) and precipitation of gypsum in Na2SO4 and CaSO4 solutions with pH values ranging from 2 to 6 at room temperature (23 ± 1 °C). The dissolution of the carbonate minerals took place at the (104) cleavage surfaces in sulfate-rich solutions undersaturated with respect to gypsum, by the formation of characteristic rhombohedral-shaped etch pits. Rounding of the etch pit corners was observed as solutions approached close-to-equilibrium conditions with respect to calcite. The calculated dissolution rates of calcite at pH 4.8 and 5.6 agreed with the values reported in the literature. When using solutions previously equilibrated with respect to gypsum, gypsum precipitation coupled with calcite dissolution showed short gypsum nucleation induction times. The gypsum precipitate quickly coated the calcite surface, forming arrow-like forms parallel to the crystallographic orientations of the calcite etch pits. Gypsum precipitation coupled with dolomite dissolution was slower than that of calcite, indicating the dissolution rate to be the rate-controlling step. The resulting gypsum coating partially covered the surface during the experimental duration of a few hours.
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Affiliation(s)
- Francesco Giancarlo Offeddu
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18-26, 08034 Barcelona, Catalonia, Spain
| | - Jordi Cama
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18-26, 08034 Barcelona, Catalonia, Spain
| | - Josep Maria Soler
- Institute of Environmental Assessment and Water Research (IDAEA), CSIC, Jordi Girona 18-26, 08034 Barcelona, Catalonia, Spain
| | - Christine V Putnis
- Institut für Mineralogie, University of Münster, Corrensstrasse 24 D-48149, Münster, Germany
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Putnis CV, Renard F, King HE, Montes-Hernandez G, Ruiz-Agudo E. Sequestration of selenium on calcite surfaces revealed by nanoscale imaging. Environ Sci Technol 2013; 47:13469-13476. [PMID: 24219361 DOI: 10.1021/es403637u] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Calcite, a widespread natural mineral at the Earth's surface, is well-known for its capacity to sequester various elements within its structure. Among these elements, selenium is important because of its high toxicity in natural systems and for human health. In the form of selenite (Se((IV))), selenium can be incorporated into calcite during growth. Our in situ atomic force microscopy observations of calcite surfaces during contact with selenium-bearing solutions demonstrate that another process of selenium trapping can occur under conditions in which calcite dissolves. Upon the injection of solutions containing selenium in two states of oxidation (either Se((IV)) or Se((VI))), precipitates were observed forming while calcite was still dissolving. In the presence of selenate (Se((VI))), the precipitates formed remained small during the observation period. When injecting selenite (Se((IV))), the precipitates grew significantly and were identified as CaSeO3·H2O, based on SEM observations, Raman spectroscopy, and thermodynamic calculations. An interpretation is proposed where the dissolution of calcite increases the calcium concentration in a thin boundary layer in contact with the surface, allowing the precipitation of a selenium phase. This process of dissolution-precipitation provides a new mechanism for selenium sequestration and extends the range of thermodynamic conditions under which such a process is efficient.
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Affiliation(s)
- Christine V Putnis
- Institut für Mineralogie, University of Münster , Corrensstrasse 24, 48149 Münster, Germany
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Wang L, Putnis CV, Ruiz-Agudo E, King HE, Putnis A. Coupled dissolution and precipitation at the cerussite-phosphate solution interface: implications for immobilization of lead in soils. Environ Sci Technol 2013; 47:13502-13510. [PMID: 24228938 DOI: 10.1021/es4041946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In situ atomic force microscopy (AFM) has been used to study the interaction of phosphate-bearing solutions with cerussite, PbCO3, (010) surfaces. During the dissolution of cerussite we observed simultaneous growth of needle-shaped or spherical pyromorphite phases. This occurred at two different pH values and ionic strengths relevant to soil solution conditions. The initial dissolution processes occurring at the cerussite solid-phosphate solution interface were clearly distinguished, and heterogeneous nucleation and growth rates of pyromorphites at phosphate concentrations ranging from 0.1 μM to 10 mM were quantitatively defined. Enhanced cerussite dissolution in the presence of high salt (NaCl or NaF) concentrations leads to an increase in pyromorphite nucleation and growth rates. The newly formed pyromorphites were found to be stable upon contact with water or citrate-bearing solutions under acidic or alkaline conditions in the pH range 4-8. These in situ observations may improve the mechanistic understanding of processes resulting in lead immobilization in diverse soil systems as well as to enhance the effectiveness of phosphate-based treatments for remediation of lead-polluted soils.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University , Wuhan, Hubei 430070, China
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Ruiz-Agudo E, Kudłacz K, Putnis CV, Putnis A, Rodriguez-Navarro C. Dissolution and carbonation of Portlandite [Ca(OH)2] single crystals. Environ Sci Technol 2013; 47:11342-11349. [PMID: 23915181 DOI: 10.1021/es402061c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The dissolution and carbonation of portlandite (Ca(OH)2) single crystals was studied by a combination of in situ Atomic Force Microscopy, Scanning Electron Microscopy, and two-dimensional X-ray diffraction. The dissolution of portlandite {0001} surfaces in water proceeds by the formation and expansion of pseudohexagonal etch pits, with edges parallel to ⟨100⟩ directions. Etch pits on {010} surfaces are elongated along ⟨001⟩, with edges parallel to ⟨101⟩. The interaction between carbonate-bearing solutions and portlandite results in the dissolution of the substrate coupled with the precipitation of thick islands of CaCO3 that appear oriented on the portlandite substrate. Ex situ carbonation of portlandite in contact with air results in the formation of pseudomorphs that fully preserve the external shape of the original portlandite single crystals. Our observations suggest that portlandite carbonation in contact with air and carbonate-bearing solutions occurs by a similar mechanism, i.e. coupled dissolution-precipitation. Calcite grows epitaxially on {0001} portlandite surfaces with the following orientation: ⟨001⟩Cc∥ ⟨001⟩Port. Apparently, no porosity is generated during the reaction, which progresses through the formation of fractures. Our results are of relevance to many processes in which the carbonation of portlandite takes place, such as CO2 capture and storage or the carbonation of cementitious materials.
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Affiliation(s)
- Encarnación Ruiz-Agudo
- Department of Mineralogy and Petrology, University of Granada , Fuentenueva s/n, 18071 Granada, Spain
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Hövelmann J, Putnis CV, Ruiz-Agudo E, Austrheim H. Direct nanoscale observations of CO2 sequestration during brucite [Mg(OH)2] dissolution. Environ Sci Technol 2012; 46:5253-5260. [PMID: 22500652 DOI: 10.1021/es300403n] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The dissolution and carbonation of brucite on (001) cleavage surfaces was investigated in a series of in situ and ex situ atomic force microscopy (AFM) experiments at varying pH (2-12), temperature (23-40 °C), aqueous NaHCO(3) concentration (10(-5)-1 M), and PCO(2) (0-1 atm). Dissolution rates increased with decreasing pH and increasing NaHCO(3) concentration. Simultaneously with dissolution of brucite, the growth of a Mg-carbonate phase (probably dypingite) was directly observed. In NaHCO(3) solutions (pH 7.2-9.3,), precipitation of Mg-carbonates was limited. Enhanced precipitation was, however, observed in acidified NaHCO(3) solutions (pH 5, DIC ≈ 25.5 mM) and in solutions that were equilibrated under a CO(2) atmosphere (pH 4, DIC ≈ 25.2 mM). Nucleation predominantly occurred in areas of high dissolution such as deep step edges suggesting that the carbonation reaction is locally diffusion-transport controlled. More extensive particle growth was also observed after ex situ experiments lasting for several hours. This AFM study contributes to an improved understanding of the mechanism of aqueous brucite carbonation at low temperature and pressure conditions and has implications for carbonation reactions in general.
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Affiliation(s)
- J Hövelmann
- Physics of Geological Processes, University of Oslo, 0316 Oslo, Norway.
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Wang L, Ruiz-Agudo E, Putnis CV, Menneken M, Putnis A. Kinetics of calcium phosphate nucleation and growth on calcite: implications for predicting the fate of dissolved phosphate species in alkaline soils. Environ Sci Technol 2012; 46:834-42. [PMID: 22136106 DOI: 10.1021/es202924f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Unraveling the kinetics of calcium orthophosphate (Ca-P) precipitation and dissolution is important for our understanding of the transformation and mobility of dissolved phosphate species in soils. Here we use an in situ atomic force microscopy (AFM) coupled with a fluid reaction cell to study the interaction of phosphate-bearing solutions with calcite surfaces. We observe that the mineral surface-induced formation of Ca-P phases is initiated with the aggregation of clusters leading to the nucleation and subsequent growth of Ca-P phases on calcite, at various pH values and ionic strengths relevant to soil solution conditions. A significant decrease in the dissolved phosphate concentration occurs due to the promoted nucleation of Ca-P phases on calcite surfaces at elevated phosphate concentrations and more significantly at high salt concentrations. Also, kinetic data analyses show that low concentrations of citrate caused an increase in the nucleation rate of Ca-P phases. However, at higher concentrations of citrate, nucleation acceleration was reversed with much longer induction times to form Ca-P nuclei. These results demonstrate that the nucleation-modifying properties of small organic molecules may be scaled up to analyze Ca-P dissolution-precipitation processes that are mediated by a more complex soil environment. This in situ observation, albeit preliminary, may contribute to an improved understanding of the fate of dissolved phosphate species in diverse soil systems.
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Affiliation(s)
- Lijun Wang
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China.
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Wang L, Li S, Ruiz-Agudo E, Putnis CV, Putnis A. Posner's cluster revisited: direct imaging of nucleation and growth of nanoscale calcium phosphate clusters at the calcite-water interface. CrystEngComm 2012. [DOI: 10.1039/c2ce25669j] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wang L, Ruiz-Agudo E, Putnis CV, Putnis A. Direct observations of the modification of calcite growth morphology by Li+ through selectively stabilizing an energetically unfavourable face. CrystEngComm 2011. [DOI: 10.1039/c1ce05091e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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